German Published Patent Application No. 42 31 449 discusses a device for controlling the drive power of an engine having at least two control units, a first control unit being connected to a first group of measuring devices and a second control unit being connected to a second group of measuring devices of the same measuring element. There may be special advantages of an engine which has two independent cylinder blocks and is controlled by two control units or controllers. Due to the fact that multiple control units are connected to only one measuring element for detection of the performance quantity, a high availability and operating reliability may be guaranteed. The system presented here having two control units has an asymmetrical functionality and program code and originally has a main computer, which is heavily utilized, and an emergency computer, which is only lightly utilized. Individual functions of the main computer are shifted to the emergency computer to optimize computation time and memory.
Instead of two controllers, German Published Patent Application No. 35 39 407 discusses a computer system having two processors for regulating characteristic quantities of an internal combustion engine. The two processors share the computer load in normal operation, each of the two processors being able to maintain emergency operation as an emergency computer in the event of malfunction. Thus, only the functions needed in emergency operation are implemented on both processors. However, in emergency operation these functions have a reduced extent of performance and function in comparison with normal operation. Due to this increased redundancy and division of work in normal computer operation, which is possible as part of the emergency function, reliability and operating speed may be increased.
Due to the asymmetrical division of functions of each controller or processor, the respective functionality must be defined, implemented, documented, tested, and maintained separately. Likewise, both controllers or computers must be equipped in the development stage with expensive measuring arrangements and/or emulation arrangements. Due to the asymmetrical definition of the functionality and therefore the asymmetrical definition of the systems, additional errors may occur due to a mix-up during assembly of the components, for example. At the same time, a further development of or change in functionality in the existing system requires that both controllers or computers and their respective functionalities be taken into account, which consequently is very complicated, time consuming and cost intensive.
This results in the object of implementing an engine control system having a very high functionality which is optimized with respect to other prior systems.